Dear Abby: I am a 22-year-old single man who recently graduated from college. I received lots of congratulations in person and by phone, text and social media.

One of them came from a woman my age named “Bree.” When I responded, I didn’t recall ever having friended her but learned she’s a cousin who lives back east. Apparently, her mother and my father are siblings.

When I asked my father about it, he got very defensive and told me whoever it was I spoke to is a complete and total liar. Ordinarily, I might have agreed, but his reaction tells me there’s a lot more to this. I want to find out more.

Neither of my parents will say a word about it, and I don’t know why. When I told them I plan to travel to the East Coast and meet Bree, I was told I may not be welcomed back if I do!

This makes me wonder what horrible thing could have happened that would make a father consider disowning his son.

Because my father won’t share the truth with me, I am left with only this option. Pursue this, find part of my family I never knew existed and learn something, but lose the family I have and regret it forever.

Any insight?

Lost Cousin in California

Dear Cousin: I can offer insight, but not a road map for how to proceed. Family secrets can be devastating. That your father reacted so strongly shows how threatened he is that you might uncover something he isn’t proud of.

As a college graduate, I am sure you are familiar with the myth about Pandora’s box. While you may not lose your father if you delve into this, you may find that when you do, your image of him may be shattered.

If you really feel you will “regret it forever” if you do, then make sure you are prepared for the possible penalty.